JP2002101389A - Method and device for recording subtitle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recording data including video data and 1st subtitle data on a recording medium so as to display the subpicture of various streams. SOLUTION: A 1st subpicture stream is copied into a DVD-VR disk as it is, and 2nd and 3rd subpicture streams are subjected to code conversion into a teletext format and incorporated into a video stream to be recorded on the DVD-VR disk. For this reason, several subtitles can be utilized in the middle of playing back the DVD-VR disk.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recording data including MPEG video data and first subtitle data on a recording medium.

[0002] The present invention also relates to an apparatus for recording such data on a recording medium.

[0003]

2. Description of the Related Art According to the generally available DVD standard, the MPEG format defines a maximum of 32 sub-picture streams. Usually, such a sub-picture stream is used to record various kinds of subtitles, for example, in different languages on a DVD disc. Thus, when playing a DVD disc, the user may select a particular subtitle displayed with the video data on the video screen.

[0004] DV using a sub-picture stream
To record multiple subtitles on a D disk,
Complex recording techniques are required. Therefore, video recorders have been developed which are capable of recording only one sub-picture stream, although the recording technique is not too complicated and not too expensive. A corresponding DVD-VR standard that describes a particular video recording on a DVD disk has been defined. A user who reproduces a video signal stored on a DVD-VR disc has one sub-picture
There is a possibility to switch the subtitle of the stream between on and off. However, the user cannot select another subtitle while playing the DVD disc.

Furthermore, according to the prior art, it is possible to "write" a subtitle into a video stream.
However, such subtitles are always visible when playing the corresponding video portion.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and makes it possible for a user to use two or more subtitles when playing a DVD-VR disc. It is intended to provide a method and apparatus.

[0007]

According to the present invention, there is provided a method of recording data including MPEG video data and first subtitle data on a recording medium. It is stored in the MPEG video data as character base information.

[0008] The effect of storing the additional subtitle data in the MPEG video stream is as follows.
The additional subtitle information is made available to the user if it has a corresponding decoder that can extract additional subtitle data from the video stream. The ability to use the subtitle data of the sub-picture stream separately is not affected by storing additional subtitle data in the MPEG video stream.

[0009] According to the improved DVD-VR standard, one or more sub-picture streams can be recorded on a DVD-VR disc. Thus, two or more subtitle streams are recorded on the disc as subpicture streams. Alternatively, two or more subtitle streams may be recorded in an MPEG video stream. For example, closed captions
This feature is provided for storing two or more subtitles.

[0010] Preferably, the subtitle data obtained from the sub-picture stream is teletext,
Stored as video text or closed captions. Teletext, video text, or
A particular advantage of using closed captions is that most television sets currently on the market already have a compatible decoder. Therefore, D
A user having a VD player and a television set with a teletext decoder can use a DVD-
Activating the first subtitle stream stored in the subtitle picture stream on the VR disc and activating the teletext decoder to activate the subtitle stream stored in the video stream as normal teletext can do.

In a preferred embodiment, the character-based subtitle information is labeled by a flag in the subtitle data, so that the corresponding data can be automatically identified as the subtitle information.

Furthermore, as described above, the video and subtitle data are recorded as digital information on a DVD disc together with further data.

The MPEG video stream provides a space for storing user data in a picture layer or a GOP (group / of picture) layer. This space is preferably used to convey or record teletext, video text or closed caption data.

The method of recording subtitle data is improved by analyzing at least one incoming subpicture stream. Such analysis is necessary to improve the conversion from sub-picture format to teletext, video text or closed caption format.

As mentioned above, the D used by the present invention
VD-VR offers the possibility to record at least two subtitle streams. Both subtitle streams are output from a DVD disc. The first subtitle stream is stored in the sub-picture stream as before. The second subtitle stream is stored, for example, as teletext. However, one subtitle stream, or all subtitle streams, can be
May be entered individually using the keyboard. In this case, the user can input an individual data stream stored on the DVD-VR disc as teletext or sub-picture data. For example, the user may enter a subtitle privately translated into another language, generate a subtitle stream for another target group, and automatically generate information associated with the content of the video stream, for example,
Record the current date and time.

Further, according to the present invention, the above method comprises:
It is incorporated in a device for recording data including MPEG video data and first subtitle data on a recording medium, and has a recording means for storing at least the second subtitle data as character-based information in the MPEG video data. Additional conversion means are provided for transcoding the subtitle data from the MPEG sub-picture format to a teletext, video text or closed caption format.

The novel method of the present invention is generally defined as a computer program and therefore runs on a number of hardware devices. For incorporation, the computer program is usually stored on a recording medium such as a data disk.

Embodiments of the present invention are shown in the accompanying drawings and are described in detail below.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to record a plurality of subtitles on a DVD-VR according to the invention, a sequence of MPEG sub-picture units is transcoded into a teletext format and then incorporated into an MPEG video stream. Such a sub-picture unit is shown in FIG. The general structure of a sub-picture unit (SPU) is the DVD standard, ie,
DVD Specifications for Read-Only Disc, Part 3, Vid
eo Specification, version 1.0, August 3, 1996, cha
pter Defined in 5.4.3 Sub-picture Unit (SPU). Accordingly, the sub-picture unit is:
Sub-picture unit header (SPUH), pixel data (PXD), and display control sequence table (S
P_DCSQT), and the display control sequence table includes a sub-picture display control sequence (S
P_DCSQ). SP_DCSQ describes the contents of display control on the pixel data. Each SP_DCSQ is:
Recorded in order and linked together.

FIG. 1 shows an example of a sub-picture unit that undergoes code conversion into a teletext signal. As specified in the above DVD standard, a specific sub-picture unit in this example starts with a sub-picture header (SPUH) containing control information. Subsequent portion PXD represents a pixel data field. In the case of this example, the pixel data is run-length coded bitmap data. The graphic field of FIG. 1 represents a subtitle graphic stored as a bitmap in the PXD.

As described above, PXD is followed by a display control sequence table (SP_DCSQT). SP_
DCSQT has several display control sequences (SP_D
CSQ). In the case of FIG. 1, SP_DCSQT is
Two display control sequences, SP_DCSQ
# 0 and SP_DCSQ # 1. An example of the contents of the display control sequence is also shown in FIG. SP_DCSQ
The start time (SP_DCSQ_STM) of # 0 is set to 0. This means that the control sequence starts at virtual time 0. Further, the next SP_DCSQ (SP
_NXT_DCSQT_SA) is shown in FIG.
Is set to SP_DCSQ # 1 shown in the right half of The display of the sub-picture unit is indicated by the command ST
Started by A_DSP. The color of each pixel type for the pixel data is set by the command SET_COLOR. In the case of this example, the color of the background pixel (bp) is set to 1 and the color of the pattern pixel (pp) is set to 0.

The contrast mixing ratio between each pixel of the pixel data and the main picture is determined by the command SET_CONT.
Set by R. In this example, the contrast is set to be maximum.

The sub-picture for displaying the sub-title needs to be arranged in the main picture. Therefore, the display area of the pixel data corresponds to the command SET_DAR.
Set by rectangle using EA. This command can individually set the X and Y coordinates of the display area. PXD to be displayed as sub-picture
Is set by the command SET_DSXPA, the address of the first pixel data used for display. The corresponding PXD start address is shown in the PXD graphic of FIG.

Sub-picture display control sequence SP_
DCSQ # 0 is terminated by a command CMD_END similarly to each SP_DCSQ.

The second and last display control sequence SP_DCSQ # 1 in the SP_DCSQT of this example is shown in the right half of FIG. The execution stop time is set to 527 units corresponding to 6 seconds. Subsequent commands related to the start address of the next sub-picture display control sequence have no effect since SP_DCSQ # 1 is the last one SP_DCSQ in this example. The command STP_DSP is used to stop the display of the sub-picture unit. As mentioned above,
Command CMD_END terminates the display control sequence.

The above-mentioned sub-picture unit is a DV
Part of the video object unit that complies with the D standard.

FIG. 2 shows a sub-picture / color look-up table expressing the relationship between a code number and a specific color. In the case of this example, the pattern pixel color is set to color “0” (see FIG. 1). The color coordinates corresponding to the color “0” are obtained from the first row of the sub-picture / color look-up table in FIG. Further, the background pixel color is set to color “1”. The corresponding color coordinates are shown in the second row of the sub-picture color look-up table. Thus, the pattern pixels and the background pixels can be set to any color.

The principle of the present invention is to convert data encoded in the MPEG sub-picture format into teletext,
The conversion to data encoded in video text or closed caption format. Therefore, all sub-picture / display control sequences should be converted to, for example, teletext format. Hereinafter, this conversion will be exemplarily described based on the conversion of the color setting value.

The teletext standard defines a small number of well-defined colors as shown in FIG. Generally, these colors are not the same as the colors in the color look-up table of FIG. Therefore, during the code conversion or conversion process, the color of the sub-picture needs to be compared with the color of the teletext. The teletext color that is most similar to the subpicture color is assigned to this subpicture color. In this example, the color "0" of the sub-picture is closest to the color "red" of the teletext.
Similarly, the subpicture color "1" is closest to the teletext color "blue". As a result, the pattern pixel color of the sub-picture unit is recorded as a red teletext color, and the background color of the sub-picture unit is recorded as a blue teletext color. In either case, the pattern pixel color and the background pixel color are
The differences are confirmed in the teletext.

Another example of the conversion of the subpicture display control sequence to the teletext standard is obtained by setting the subtitle area in the main picture. FIG.
According to the sub-picture unit of SET_DAR
EA is set to x = 40-679 and y = 488-527. The transcoding needs to find a teletext line that essentially corresponds to the area defined in the sub-picture unit. In the case of this example, this area corresponds to the teletext line 22. Thus, the subtitle "H
Hello World! "Is displayed in the teletext line 20.

Conversion of a DVD sub-picture to the teletext subtitle format requires analysis of the sub-picture for the following reasons. Sub-picture
The unit includes a run length compressed bitmap data unit and additional presentation commands. The presentation command of the sub-picture unit is directly converted into a corresponding teletext command. However, in the case of the sub-picture format, the subtitle information is stored as bitmap data, and in the case of the teletext format, the subtitle information is stored as background and characters. Therefore,
To convert a subtitle from sub-picture format to teletext format, it is necessary to recognize the drawn text.

Pattern recognition of computer generated text as shown in FIG. 4 is well known in the art. In the case of a DVD sub-picture, pattern recognition is simplified because only four pixel types are used. Furthermore, the specific assignment of sub-picture pixels for special purposes, ie background pixels, pattern pixels, enhanced one pixel and enhanced two pixels, further helps to simplify pattern recognition. As a result, the pixel data bitmap of the sub-picture unit in this example is converted into a character sequence "Hello World!" By pattern recognition.

As mentioned above, the sub-picture stream needs to be parsed to convert the data to teletext format. Such an analysis is performed according to the flowchart shown in FIG. The analysis process shown in FIG. 5 is used for most types of subtitle sub-pictures having two SP_DCSQs. Generally, the subtitle subpicture unit does not include a command (CHH_COLCON) for changing the color and contrast of the pixel data. Thus, the following procedure is performed during the analysis process.

At step 1, a command for proceeding to the sub-picture display control sequence SP_DCSQ # 0 is executed.

In step 2, the colors to be used are obtained from the command SET_COLOR.

In step 3, the colors of the assigned subpicture color look-up table are compared with the teletext colors (red, green, yellow, etc.). Furthermore, the teletext colors are assigned as clearly as possible to the sub-picture colors used in the analyzed sub-picture stream. Such an assignment ensures that in most cases the teletext color is similar to the sub-picture color.

In step 4, the value SET_DAREA is analyzed to obtain the screen location of the sub-picture. Subsequently, a teletext line appearing near the screen location of the sub-picture is selected.

In step 5, pattern recognition of the run-length coded PXD bitmap is started. Value SE
T_DSPXA is used to detect the start position of the run length coded bitmap of the upper field and the lower field inside the PXD. Value SET_DAREA
Is used to obtain the number of pixels per row. Next, the bitmap is analyzed using a pattern recognition algorithm to detect characters in the bitmap.

In step 6, a teletext color that matches the subpicture color is assigned to the subtitle text and background.

Finally, in step 7, the end of the representation of the sub-picture is set to ST in the last SP_DCSQ.
SP_DCSQ value SP_D including P_DSP command
Obtained from CSQ_STM.

The formula for calculating the interval in seconds is SP_DCSQ_STM * 64/5625. The teletext subtitle is deleted after this presentation time, and a blank teletext page or the next teletext subtitle is displayed on the screen.

In the case of karaoke, the phrase or word to be sung at that moment is emphasized in the subtitle. In this case, steps 2 and 7 are changed as follows.

In step 2, all SET_COLOR commands and all CHs of the sub-picture unit
The G_COLCON command is read. Step 7
Then, the subtitle presentation step, that is, the karaoke emphasis step, is searched until the presentation of the entire subpicture is completed. Karaoke highlight step is new C
SP_DCSQ value S for each HG_COLCON command
Defined by P_DCSQ_STM. As described above, the presentation end of the sub-picture is determined by the last SP_PCS.
Defined by the value of Q SP_DCSQ_STM. The formula for calculating the interval of each step in seconds from the start of the sub-picture unit is the same as the above formula. After each presentation step, a new teletext subtitle with another emphasis or a blank text page should be displayed or a new text subtitle should be sent.

The analysis of the sub-picture data must be further modified if the sub-picture unit defines a large number of subtitles. In particular, Steps 2 and 7 are changed in the same manner as in the case of karaoke, and since there are a large number of subtitles, the end of the presentation of the sub-picture is determined by the next appearing SP_DCSQ value SP_DCSQ_S including the STP_DSP command.
Defined by TM.

Further, as shown by the dashed lines in FIG. 5, multiple subtitles of a sub-picture unit require an additional step 8 with the following branch condition. That is, the currently analyzed S including the STP_DSP command
If the next higher SP_DCSQ exists after the P_DCSQ, the current SP including this STP_DSP command
The process proceeds to SP_DCSQ immediately after _DCSQ, and repeats from step 4.

Analysis of the sub-picture stream is the basis for transcoding sub-picture units into teletext, video text, or closed captions. Since the sub-picture unit is part of the sub-picture stream, the corresponding commands of the sub-picture unit need to be permanently analyzed as they are changed. The effects caused by this are as follows.

A) Each SET_DAREA command that occurs requires a change in the subtitle location on the teletext screen.

B) Each SET_DSPXA command that occurs requires a new execution of the pattern recognition process.

C) Each SET_COLOR command that occurs requires a change in text color.

D) Each CHG_COLCON command that occurs requires a change in the text color of certain characters.

E) Each SET_CONTR command that occurs requires the prohibition or permission of the teletext subtitle.

F) Each appearing STP_DSP requires prohibition of teletext subtitles.

G) Each appearing STA_DSP needs permission for teletext subtitles.

Normally, each event from events a) to g) is
Request a change to the current teletext subtitle page.

The transcoding process creates the data structures required by the teletext, video text, or closed caption standards. In the case of this example, the code conversion results in a teletext data structure as shown in FIGS. 6 and 7, which represents two representative lines of teletext.

FIG. 6 shows teletext line 0 obtained from the sub-picture unit of FIG. The general structure of a teletext signal is defined by international teletext standards. According to this, the teletext signal for one page includes 24 rows. The first row 0 contains control information, like the header. This line is formed by a sequence of two hexadecimal digits. At the beginning of the line, the first three digits representing the clock run-in and the framing code are fixedly set for a given type of teletext. The next magazine number “2” indicates the hundreds digit of the teletext page number. The next teletext number represents the line number. The next two numbers represent the tens and ones digits of the teletext page number. The number of the subpage of the teletext page is encoded in the next four hexadecimal numbers. Control codes for subtitles, new pages, etc. follow.

The next line of the teletext signal contains specific information provided by the broadcast facility. Typically, the subtitle information is sent to the last visible line. An example of such a subtitle teletext line is shown in FIG. Row 22 further includes a hexadecimal sequence. The beginning of row 22 is the same as the beginning of row 0;
Includes clock run-in and framing code. The next hexadecimal number represents the magazine number and line number. The next numbers are the code for the background color, the code for the character set color, and the characters to be displayed.

As can be seen from the above description, a teletext signal is a hexadecimal sequence divided into several lines. Each codeword has a specific meaning, such as a page number, subtitle, or background color.

The above-described code conversion process for converting sub-picture data into teletext data is a basic matter for incorporating a subtitle stream into an MPEG video stream according to the present invention. Incorporation of subtitle stream into video stream
This will be described using the following example with reference to FIG.

The DVD video disk stores a movie including two subtitle streams of English subtitle stream SP # 1 data and German subtitle stream SP # 2 data. This movie is a DVD-VR
Consider the case of copying to a disk. The first subtitle stream corresponding to English is stored on the DVD video disc as a sub-picture stream, and the DVD-V is recorded as sub-picture stream SP # 1 data.
It is copied to the R disk (see FIG. 8). The second subtitle stream corresponding to German is code-converted into teletext subtitle data, and the DVD-V
It is recorded as a teletext stream as specified in the R specification, version 1.0. As a result,
The data unit of the audio and video stream AV data and the data unit of the second sub-picture stream SP # 2 data of the DVD video data are DV
It is combined with an audio-video-teletext stream (AV data and teletext data) of D-VR data. Further, the first sub-picture stream SP # 1 data of DVD video data is copied to the sub-picture stream SP # 1 of DVD-VR data without code conversion.

As described above, the present invention has an advantage over the conventional DVD-VR in that two independent subtitle streams can be recorded on a DVD-VR disc instead of one per video object. It works. Furthermore, the data conversion according to the invention is completely compatible with the DVD-VR specification, as shown in FIG. Finally, the present invention can be used without additional hardware, since the entire data conversion is performed by software only.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a sub-picture unit including sub-title information.

FIG. 2 is an explanatory diagram of a typical color lookup table.

FIG. 3 is an explanatory diagram of a typical teletext color table.

FIG. 4 is a diagram illustrating the principle of pattern recognition.

FIG. 5 is an explanatory diagram of sub-picture data analysis processing according to the present invention.

FIG. 6 is an explanatory diagram of a 0th line teletext corresponding to the sub-picture unit of FIG. 1;

FIG. 7 is an explanatory diagram of a 22nd-line teletext corresponding to the sub-picture unit in FIG. 1;

FIG. 8 is an explanatory diagram of integration of subtitle data into MPEG video data according to the present invention.

 ──────────────────────────────────────────────────の Continuation of the front page (71) Applicant 300000708 46, Quai A, Le Gallo F-92648 Boulogne Cedex France (72) Inventor Dirk Adorf, Germany, 30952 Ronenberg, Walblink 2F Term (Reference) 5C052 AA02 AB04 CC01 CC11 DD04 5C053 FA24 GB12 GB37 JA16 KA05 5D044 AB05 AB07 AB09 BC04 CC06 DE17 DE53 EF05 GK08 5D077 AA30 CA11 DE05 DE10 HC17

Claims (18)

[Claims] The video data and at least one first
A method of recording data including the subtitle data of claim 1 on a recording medium, wherein at least one second subtitle data is stored in the video data as character-based information. 2. A method for analyzing at least one subpicture stream including the second subtitle data before recording the second subtitle data, and converting the second subtitle data into character-based information. The method of claim 1, comprising: 3. The second subtitle data is transcoded or encoded as teletext, video text, or closed caption data.
The method of claim 2. 4. The method according to claim 1, further comprising a step of labeling the character-based information using a flag in the subtitle data. 5. The method according to claim 1, wherein the video data and the subtitle data are recorded as digital information on a DVD disc. 6. The video data encoded according to the MPEG video standard, comprising picture layer or GOP layer user data, and wherein the second subtitle data is stored in the user data. The method according to any one of claims 1 to 5. 7. The method according to claim 1, wherein the at least one first subtitle data is recorded as a sub-picture stream. 8. The method according to claim 1, wherein the subtitle data includes user-defined subtitle information. 9. The video data and at least one first
An apparatus for recording data including subtitle data on a recording medium, the recording apparatus recording at least one second subtitle data as character-based information in the video data. 10. A means for analyzing at least one sub-picture stream including the second subtitle data before recording the second subtitle data, and converting the second subtitle data into character-based information. 10. The apparatus of claim 9, further comprising: means. 11. The method according to claim 10, wherein said converting means includes means for transcoding or encoding said second subtitle data as teletext, video text, or closed caption data. apparatus. 12. The apparatus according to claim 9, further comprising: means for labeling the character-based information using a flag in the subtitle data. 13. The recording means according to claim 9, wherein said recording means includes means for recording at least said video data and said subtitle data as digital information on a DVD disk.
3. Apparatus according to any one of the preceding claims. 14. The method according to claim 1, wherein the character-based information is a picture picture of the video data encoded according to the MPEG video standard.
Apparatus according to any of claims 9 to 13, further comprising means for inserting into layer or GOP layer user data. 15. The apparatus according to claim 9, further comprising: a unit for recording the at least one first subtitle data as a sub-picture stream. 16. The apparatus according to claim 9, further comprising means for inserting user-defined subtitle information into said subtitle data.
16. The device according to any one of claims 15 to 15. 17. A computer program for causing a computer to execute the method according to claim 1. Description: 18. A recording medium on which the computer program according to claim 18 is recorded.